Measure concentrations and cumulative amounts of parent drug and metabolite in plasma, urine, feces, and relevant body tissues as feasible in animals and man. Determine drug-tissue interactions such as plasma protein binding, tissue binding, lipid soluability, etc. of parent drug and its metabolites. Quantitate physcologic functions which are important in determining drug and metabolite kinetic characteristics. A kinetic model which interrelates the above findings in a quantitative manner should be developed.